"I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet. Scientists have been looking for this missing deep water for decades."

Interestingly this isn't a reservoir in the conventional sense; there isn't a vast floating ocean underneath America. And no, there are no dinosaurs wandering its shores.

Instead the water is trapped inside the molecular structure of minerals found within the mantle rock.

Incredibly if just 1% of the Earth's mantle rock contained H2O that would amount to three times the amount of water that's in our oceans.

It's believed the mineral was brought up from a depth of around 400 metres below the Earth's surface. What scientists found when they analysed it was a surprising amount of water was actually trapped inside.

"The ringwoodite is like a sponge, soaking up water, there is something very special about the crystal structure of ringwoodite that allows it to attract hydrogen and trap water. This mineral can contain a lot of water under conditions of the deep mantle."

To give you some idea of just how little we know about our own planet, that sample of ringwoodite is the only known sample of it to have come from within the Earth.

PICS: Space Is Incredible

PICS: Space Is Incredible

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Europa

The icy surface of Europa is shown strewn with cracks, ridges and "chaotic terrain," where the surface has been disrupted and ice blocks have moved around. New laboratory experiments show that water ice and frozen sulfur dioxide react even at the frigid temperatures of Europa. Because the reaction occurs without the aid of radiation, it could take place throughout the moon's thick ice layer—an outcome that would revamp current thinking about the chemistry and geology of this moon and perhaps others.